msm: pcie: add option to disable L1ss TO for DRV suspend

There are usecases where clients will not want DRV subsystem
to enable L1ss inactivity timeout. Provide PCIe clients the
option to disable L1ss inactivity timeout when requesting a DRV
suspend.

Change-Id: I940526a58bb2496529e919b5b602c0bc31ca9ae1
Signed-off-by: Tony Truong <truong@codeaurora.org>